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Tip #613: Blu-ray Disc File Formats

… for Codecs & Media

Tip #613: Blu-ray Disc File Formats

Larry Jordan – LarryJordan.com

The most popular distribution format for Blu-ray Disc is H.264/AAC.

The Blu-ray Disc logo.

Topic $TipTopic

Continuing our look at Blu-ray Discs that we started in Tip #612, here’s a list of supported codecs for Blu-ray Discs.

NOTE: You can use any media format for mastering, but files for distribution must use one of these formats.

According to this Sony website, the following audio and video codecs are supported on Blu-ray Disc® media.

Video Codecs

  • MPEG-2: Enhanced for HD, also used for playback of DVDs and HDTV recordings.
  • MPEG-4 AVC: Part of the MPEG-4 standard also known as H.264 (High Profile and Main Profile).
  • SMPTE VC-1: A standard based on Microsoft® Windows Media® Video (WMV) technology.

Audio Codecs

  • Linear PCM (LPCM): Offers up to 8 channels of uncompressed audio.
  • Dolby Digital® (DD): Format used for DVDs also known as AC3, offers 5.1-channel surround sound.
  • Dolby Digital® Plus (DD+): Extension of DD, offers increased bitrates and 7.1-channel surround sound.
  • Dolby® TrueHD: Extension of MLP Lossless, offers lossless encoding of up to 8 channels of audio.
  • DTS Digital Surround®: Format used for DVDs, offers 5.1-channel surround sound.
  • DTS-HD®: Extension of DTS, offers increased bitrates and up to 8 channels of audio.

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Tip #588: What is ProRes?

… for Codecs & Media

Tip #588: What is ProRes?

Larry Jordan – LarryJordan.com

ProRes is a good choice for capture, editing and master files.

The Apple ProRes logo.

Topic $TipTopic

Apple ProRes codecs provide a combination of multistream, real-time editing performance, impressive image quality, and reduced storage rates. ProRes codecs take full advantage of multicore processing and feature fast, reduced-resolution decoding modes. All ProRes codecs support any frame size (including SD, HD, 2K, 4K, 5K, and larger) at full resolution. The data rates vary based on codec type, image content, frame size, and frame rate.

As a variable bit rate (VBR) codec technology, ProRes uses fewer bits on simple frames that would not benefit from encoding at a higher data rate. All ProRes codecs are frame-independent (or “intra-frame”) codecs, meaning that each frame is encoded and decoded independently of any other frame. This technique provides the greatest editing performance and flexibility.

A variety of cameras can now capture and record a wider gamut of
color values when working in log or raw formats. You can preserve a wider color gamut by recording with the ProRes LOG setting on certain cameras such as the ARRI ALEXA or transcoding from the RED® camera’s REDCODE® RAW format. This results in deeper colors and more detail, with richer red and green areas of the image.

EXTRA CREDIT

Here’s an Apple White Paper that explains ProRes in more detail.

The table of file sizes, at the end, are invaluable in planning storage requirements.

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Tip #589: Pick the Right Version of ProRes

… for Codecs & Media

Tip #589: Pick the Right Version of ProRes

 Larry Jordan – LarryJordan.com

I recommend ProRes 422 for camera media and ProRes 4444 for computer media.

The Apple ProRes logo.

Topic $TipTopic

Apple provides this description of the six different versions of ProRes:

Apple ProRes 4444 XQ: The highest-quality version of ProRes for 4:4:4:4 image sources (including alpha channels), with a very high data rate to preserve the detail in high-dynamic-range imagery generated by today’s highest-quality digital image sensors.

Apple ProRes 4444: An extremely high-quality version of ProRes for 4:4:4:4 image sources (including alpha channels). This codec features full-resolution, mastering-quality 4:4:4:4 RGBA color and visual fidelity that is perceptually indistinguishable from the original material. Apple ProRes 4444 is a high-quality solution for storing and exchanging motion graphics and composites, with excellent multi-generation performance and a mathematically lossless alpha channel up to 16 bits.

NOTE: Apple ProRes 4444 XQ and Apple ProRes 4444 are ideal for the exchange of motion graphics media because they are virtually lossless, and are the only ProRes codecs that support alpha channels.

Apple ProRes 422 HQ: A higher-data-rate version of Apple ProRes 422 that preserves visual quality at the same high level as Apple ProRes 4444, but for 4:2:2 image sources.

Apple ProRes 422: A high-quality compressed codec offering nearly all the benefits of Apple ProRes 422 HQ, but at 66 percent of the data rate for even better multistream, real-time editing performance.

Apple ProRes 422 LT: A more highly compressed codec than Apple ProRes 422, with roughly 70 percent of the data rate and 30 percent smaller file sizes. This codec is perfect for environments where storage capacity and data rate are at a premium.

Apple ProRes 422 Proxy: An even more highly compressed codec than Apple ProRes 422 LT, intended for use in offline workflows that require low data rates but full-resolution video.

My general recommendation is to use ProRes 422 for all images shot on a camera (except RAW formats), and ProRes 4444 for all media converted from RAW or Log or media generated on a computer.

EXTRA CREDIT

Here’s an Apple White Paper that explains ProRes in more detail.

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Tip #590: What is a Proxy File?

… for Codecs & Media

Tip #590: What is a Proxy File?

 Larry Jordan – LarryJordan.com

Proxy files allow editing on slower systems, using less storage.

Topic $TipTopic

Proxy files are designed to be smaller, easy-to-edit media files when compared to camera native. But what does “easy-to-edit” and “smaller” actually mean?

EASY TO EDIT

There are two ways to compress video:

  • GOP (also called “inter-frame compression”) compresses images in groups. This creates very small file sizes, but requires more CPU performance to edit because the computer needs to deconstruct each group before it can edit a specific frame.
  • I-frame (also called “intra-frame compression”) compresses each frame individually. This creates larger files, but even slower systems can edit them smoothly because each frame is immediately available for editing.

All proxy files use I-frame compression, which decreases the load on the CPU and speeds editing.

SMALLER

Proxy files are 1/4 the resolution of the camera native media, which decreases the load on storage system capacity and bandwidth. For example, a proxy file for a 1920 x 1080 frame is only 960 x 540 pixels. This reduces storage bandwidth by 75%.

However, this reduced resolution also means that proxy files should not be used for final output because they don’t have the full resolution of the master file.

SUMMARY

Both Premiere and Final Cut support seamless proxy editing, which is recommended for larger frame sizes and multicam editing. Then, for final output, switch from the proxy to high-quality files to get the best images from your project.

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Tip #565: Frame Rate Does Not Create Motion Blur

… for Codecs & Media

Tip #565: Frame Rate Does Not Create Motion Blur

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Motion blur is based on shutter speed, not frame rate.

Topic $TipTopic

A frequent email from filmmakers asks about how to change their project’s frame rate to make it more “cinematic.” Specifically, they are looking to convert to 24 fps. The problem is that changing the frame rate will only make a video look worse.

Motion blur, which is a slight blurring of the edges of a moving object, is caused by something moving while the shutter is open. If the shutter speed is slow, meaning the shutter is open for a longer time, the motion blur is exaggerated. If the shutter speed is fast, the motion blur is minimized.

Changing the frame rate after an image is recorded won’t affect motion blur. Motion blur is determined at the moment the original image is recorded.

Changing the frame rate after a clip is recorded can only be done by removing or adding frames. For example, changing the frame rate from 30 fps to 24 fps means that every fifth frame of the original media will be removed. There’s no other way to do this, you can’t “reallocate” frames to match a different frame rate; you can only drop or add them.

In the case of dropping frames, this means that the video will have a slight “stutter” every five frames, which will mess with any kind of smooth camera move.

The moral of this story is: shoot the frame rate you need to deliver and don’t change frame rates after the fact.

EXTRA CREDIT

The web supports any frame rate you can upload, unlike broadcast or cable. There’s no benefit to converting frame rates.

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Tip #577: VoIP Audio is Not High-Quality

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Tip #577: VoIP Audio is Not High-Quality

Larry Jordan – LarryJordan.com

Codecs are also why our phones work.

Topic $TipTopic

We’ve all heard of codecs. These convert audio, or video, from analog into digital signals and back.

Just as codecs are the heart of digital visual media, they are also at the heart of VoIP, which stands for Voice over IP. This technology is what allows you to connect a telephone to the Internet and have it actually work.

An audio codec works its magic by sampling the audio signal several thousand times per second. For instance, a WAV codec samples the audio at 64,000 times a second. It converts each tiny sample into digitized data and compresses it for transmission. When the 64,000 samples are reassembled, the pieces of audio missing between each sample are so small that to the human ear, it sounds like one continuous second of audio signal.

What I learned recently is that the codecs used for VoIP don’t sample at 64,000 samples per second. Rather, they sample at 8,000 samples per second. According to the Nyquist theorem, if you divide the sample rate by 2, that yields the maximum frequency response for that sample rate. This means that the maximum high frequency carried by most VoIP systems is 4,000 Hz. This is well below the frequency range of many consonants, such as “S” and “T.”

EXTRA CREDIT

In case you were wondering, codecs use advanced algorithms to help sample, sort, compress and packetize audio data. The CS-ACELP algorithm (CS-ACELP = conjugate-structure algebraic-code-excited linear prediction) is one of the most prevalent algorithms in VoIP. CS-ACELP organizes and streamlines the available bandwidth. Annex B is an aspect of CS-ACELP that creates the transmission rule, which basically states “if no one is talking, don’t send any data.” The efficiency created by this rule is one of the greatest ways in which packet switching is superior to circuit switching. It’s Annex B in the CS-ACELP algorithm that’s responsible for that aspect of the VoIP call.

And, no, that won’t be on the quiz.

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Tip #578: Media Codec Issues on Windows

… for Codecs & Media

Tip #578: Media Codec Issues on Windows

Larry Jordan – LarryJordan.com

Windows Media Player has its own challenges in finding and playing codecs.

Topic $TipTopic

Windows Media Player includes some of the most popular codecs, like MP3, Windows Media Audio, and Windows Media Video. However, it doesn’t include the codecs required for Blu‑ray Disc files, FLAC files, or FLV files. If something isn’t working in Windows Media Player, you might not have the right codec on your PC. The easiest way to fix this problem is to go online and search for the codec you need.

How can I find out which codecs are installed on my PC?

  1. On the Help menu in Windows Media Player, select About Windows Media Player. If you don’t see the Help menu, select Organize > Layout > Show menu bar.
  2. In the About Windows Media Player dialog box, select Technical Support Information. Your web browser will open a page that includes a lot of detailed info about the related binary files, codecs, filters, plug-ins, and services installed on your PC. This info should help you troubleshoot problems.

How do I tell which codec was used to compress a file and what format a file is in?

There isn’t a way to determine with absolute certainty the codec used to compress a file, but the following are your best options:

  • To determine what codec was used with a specific file, play the file in the Player, if possible. While the file is playing, right-click the file in the library, and then select Properties. On the File tab, look for the Audio and Video codec sections.
  • Use a non-Microsoft codec identification tool. To find one, search for “codec identification tool” on the web. You’ll find several tools as well as useful related info.

You might be able to tell the format of a file by looking at the file name extension (such as .wma, .wmv, .mp3, or .avi). However, there are limits to this approach. Many programs create files with custom file extensions. And it’s possible for anyone to rename a file without changing the file’s format. A file with an .mpg or .dvr-ms extension, for example, is usually just an AVI file that’s been compressed by using some version of an MPEG video codec.

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Tip #559: What is “Frame Reordering” in Apple Compressor?

… for Codecs & Media

Tip #559: What is “Frame Reordering” in Apple Compressor?

Larry Jordan – LarryJordan.com

This defaults to on. Leave it that way.

The Frame Reordering option in Apple Compressor.

Topic $TipTopic

Ever wonder what Frame Reordering does in Apple Compressor? Me, too. So, I did some research. Here’s what I learned.

Frame reordering is the concept of allowing frames to be decompressed in a different order than their display order. For almost all cases, leave this box checked for H.264 encoding. Some more advanced compressors use “frame reordering” to more efficiently represent movie data.

Important: If you select “Allow frame reordering,” your output file may be more efficiently compressed but may not be compatible with decoders on older hardware. For example, if someone asks you to create your content with “B-frames turned off.”

In looking at YouTube’s latest upload specs, they make no mention of this setting. My suggestion is to leave it on unless you are specifically required to turn it off.

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Tip #560: What is “Clean Aperture” in Apple Compressor?

… for Codecs & Media

Tip #560: What is “Clean Aperture” in Apple Compressor?

Larry Jordan – LarryJordan.com

This option should be off for most media today.

Uncheck “Add clean aperture information” when working with digital media.

Topic $TipTopic

One of the checkboxes in Apple Compressor is “Add clean aperture information.” What is this and should it be checked or unchecked?

Apple’s Help Files state: Select this checkbox to define clean picture edges in the output file. This property adds information to the output file to define how many pixels to hide, ensuring that no artifacts appear along the edges. When you play the output file in QuickTime Player, the pixel aspect ratio will be slightly altered. This process doesn’t affect the actual number of pixels in the output file—it only controls whether information is added to the file that a player can use to hide the edges of the picture.

For example, this setting would clean up edges from a VHS tape transfer that waver.

YouTube, on the other hand, prefers this option be unchecked to prevent the video from being cropped during playback.

My suggestion: If you are dealing with digital media with clean edges, uncheck this before starting compression.

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Tip #561: Optimize Compression Settings for YouTube

… for Codecs & Media

Tip #561: Optimize Compression Settings for YouTube

Larry Jordan – LarryJordan.com

In most compression software, the optimal settings are not the default.

Video compression bitrates for YouTube for SDR media.

Topic $TipTopic

Here are settings you can use to optimize audio and video compression for YouTube. (These are based on published settings from YouTube, a link to which is below.)

Container: MP4

Video codec: H.264

  • Progressive (deinterlace interlaced media)
  • High Profile
  • Closed GOP
  • Variable bit rate
  • Chroma subsampling: 4:2:0

Audio codec: AAC-LC (AAC if no LC choice is available)

  • Bit rate: 384 Kbps stereo / 128 Kbps mono

Frame rate: The frame rate you shot. Do NOT convert frame rates.

Bit rate: See screen shot for table.

If given the choice:

  • Turn off mulitpass compression if your hardware is more recent than 2015.
  • Turn on Frame Reordering
  • Turn off Add clean aperture information

NOTE: These settings differ from the YouTube default settings in Apple Compressor.

EXTRA CREDIT

Here’s the link to YouTube’s Support Site with more details.

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